Refrigerating apparatus



y 1939- F. R. ERBACH ETAL 2,158,793

- REFRIGERATING APPARATUS Filed March 10, '1937 3 Sheets-Sheet 1' May 16, 1939. F. R. ERBACH ET AL REFRIGERATING APPARATUS 5 Sheets-Sheet 2 Filed March" 10, 1957 y 1939- F. R. ERBA CH ET AL REFRIGERATING APPARATUS Filed March 10, 1957 3 Sheets5heet 3 iii v Q HF L) U Q U ImJeIZZZrfied z Erbczcfa s LS3 Patented May 16, 1939 UNITED STATES TENT OFFECE REFRIGERATING APPARATUS ware Application March 10,

5 Claims.

The invention relates to refrigerating apparatus and has particular reference to evaporator structure that can be assembled from complete evaporator units of standard size making it pos- 5 sible to build evaporators on the job where the refrigerating apparatus is being installed and of a size to suit the particular requirements of installation.

A more specific object of the invention is to provide evaporator structure that can be assembled from standard size units characterized by a plurality of evaporator passages arranged in parallel and having connection to a common suction header and which are also supplied with liquid refrigerant from a single expansion valve in a manner to insure uniform distribution of the liquid refrigerant.

Another object of the invention is to provide complete evaporator units of standard size hav- 20 ing flanged end fins with uniformly spaced bolt openings for receiving securing means whereby the end fins of one unit can be readily secured to the end fins of another unit to produce evaporator structure of any desired capacity. In 25 structure comprising several complete evaporator units said units are connected in parallel to the liquid refrigerant supply line and suction line.

The invention further contemplates improvements in the expansion valve for each evaporator 30 unit and has more particular reference to an improved distributor head for efficiently and uniformly distributing liquid refrigerant to a plurality of evaporator passages arranged in parallel and joining with a common suction header.

Another object is to secure uniform distribution of the refrigerant by feeding the refrigerant to a header having connection with a plurality of pressure regulating tubes by which the liquid refrigerant is distributed to the evaporator passages and which restricts the flow of the refrigerant from the header, thereby maintaining a sufiiciently high pressure to prevent evaporation of the refrigerant in the header. The uniformity of refrigerant distribution from the various pres sure regulating tubes of the liquid fed header can be still further improved by pre-cooling the liquid refrigerant admitted to the header. This is accomplished by providing a heat interchanger between the liquid refrigerant supply and the suction line by which heat will be removed from the liquid refrigerant by the cool refrigerant gas being conducted to the compressor. With pre-cooled liquid in the header a wide range of header pressure is possible under varying operat- 1937, Serial No. 130,028

ing conditions without interfering with the unifcrmity of refrigerant distribution.

A further object resides in the provision of a novel distributor head which will impart a whirling motion to the liquid refrigerant to thereby more uniformly feed the liquid refrigerant to the plurality of pressure regulating tubes connecting with said head.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the invention and wherein like reference characters are used to designate like parts Figure 1 is a horizontal sectional view taken through an individual evaporator unit embodying the features of the present invention;

I Figure 2 is a front elevational view of the individual evaporator unit shown in Figure 1;

Figure 3 is a longitudinal sectional view showing the improved distributor head applied to a conventional expansion valve;

Figure 4 is an elevational view of a novel distributor head;

Figure 5 is a rear elevational view showing evaporator structure comprising three individual evaporator units; and

Figure 6 is a front elevational view of the evaporator structure of Figure 5.

The invention is concerned with the provision of unit evaporators which may be suitably secured together at their respective ends to comprise an evaporator assembly wherein each unit is in parallel, having connection with a common liquid refrigerant supply line and suction line. The individual evaporator units may be of any size desired although it is contemplated that certain sizes will be standard equipment. As shown in Figures 1 and 2 the evaporator unit selected for illustration may consist essentially of a plurality of coils I each comprising straight lengths of copper tubing H joined to each other by return bends l2 so as to form a continuous length of tubing from the inlet end l3 to the outlet 14. The particular evaporator disclosed consists of four coils horizontally disposed and spaced substantially equi-distant apart. The straight length of tubing ll of each coil passes through openings formed in the flanged end fins i and H5 which thereby locates the return bends l2 to the outside of said end fins. The coils between said end members are provided with a plurality of fins I'I equally spaced and of any suitable metal such as copper which materially adds to the surface of the tubes and aids in the refrigeration of air or other medium brought into contact with said tubes or fins.

The end members l and I5 are each provided with flanges 18 extending outwardly from each side thereof. The top and bottom flanges of each member are apertured as at 28, forming bolt openings for receiving bolts whereby the end members of adjacent units may be joined. In accordance with the invention the size of the openings and the spacing between openings is uniform for the evaporator units so that two or more can be readily bolted together to form an evaporator assembly such as shown in Figures 5 and 6.

The coils l6 of the individual evaporator units are connected at their outlet end Hi to a common suction header 2|. At an intermediate point the suction header has connection with the suction conduit 22 horizontally disposed and extending to the opposite side of the unit. On this side the end members I5 and I6 of the unit are cut away, as at 23, forming a U-shaped recess through which the suction conduit extends, the same projecting beyond the rear of the unit and joining with the suction line 24. That portion of the suction conduit extending between the end members I5 and I5 is provided with a heat interchanger designated in its entirety by numeral 25, which essentially consists of an outer concentric conduit 26 having closed ends 21. The space surrounding the suction conduit 22 and within the outer conduit 25 is adapted to contain liquid refrigerant delivered thereto by the liquid refrigerant supply line 28 connecting with said heat interchanger at 3B. The outlet for said heat interchanger PM is located at the opposite end thereof and thus the liquid refrigerant in its travel through the heat interchanger will be subjected to the cooling effect of the cool refrigerant gas flowing through the suction conduit. The outlet 3| joins with the expansion valve, to be particularly described, and as a result of the heat interchanger liquid refrigerant is delivered to the expansion valve at a much lower temperature than would otherwise be the case. In fact, the refrigerant is cooled to very nearly evaporator temperature.

A short section of tubing 32 joins the outlet 3| of the heat interchanger with a conventional expansion valve designated in its entirety by 33 which is shown in detail in Figure 3. Said valve consists of a body portion 34 having an inlet 35 which receives the end of tube 32 and supplies liquid refrigerant to said valve. A conical valve member 35 formed on the end of rod 31 controls the flow of liquid refrigerant to the outlet header 38 within which is located a distributor head 40, as more particularly shown in Figure 4. The liquid refrigerant in the header first passes through the screen 41 and is then delivered by a plurality of openings 42 to a chamber 43 formed by said distributor head and the cylindrical walls of the header 38. The base of said chamber is provided and as said orifices have the same level, equal quantities of liquid refrigerant will be delivered to the pressure regulating tubes.

Referring more particularly to the expansion valve, the same is provided with a pressure responsive diaphragm 48 which has connection with the valve member 35 through the rod 31. Said diaphragm is biased toward the right in a valve opening direction by the pressure produced by the thermostatic bulb 49, which pressure is communicated through the capillary tube 55 to the space on the upper side of diaphragm 48. As shown in Figure 1, the thermostatic bulb 49 is clamped by members 5| to the suction outlet 22 and thus the average discharge temperature of the refrigerant gas leaving the plurality of cool; ing coils l8 influences the thermostatic fluid in said bulb to produce corresponding variations in pressure on the upper side of the diaphragm, opening the valve admitting liquid refrigerant to the outlet header. However, the diaphragm 48 is biased toward the left in a valve closing direction by the pressure of the evaporated refrigerant gas within the suction header 2|, which pressure is communicated from said header through tube 52 having connection with the body portion of the expansion valve through nipple 53. Accordingly, the space on the underside of the diaphragm 48 is equalized with the pressure of the evaporated refrigerant gas, which pressure op.- poses that of the thermostatic expansion bulb to cause closing of the valve. Also the coil spring 54 yieldingly forces the valve member 36 in a closing direction. The tension of the spring 54 can be adjusted by member 55 having a slot 56 in its projecting end for receiving any suitable tool by which the member can be rotated.

In operation of the thermostatic expansion valve above described it may be assumed that at the start of the refrigeration cycle the evaporator will be comparatively warm and the suction gas will therefore be superheated. Since the pressure produced by the thermostatic bulb 49 is proportional to its temperature, the pressure on the upper side of the diaphragm will therefore be greater than the evaporating pressure, causing the valve to open. Below the diaphragm the suction pressure of the system is transmitted through the external equalizer connection and this pressure together with the tension of the coil spring 54 will oppose the bulb pressure. As the evaporator cools the pressure above the diaphragm will decrease and the thermostatic valve will close in proportion to this reduction in pressure. The difference in pressure imposed on the diaphragm is a function of the superheat of the refrigerant leaving the series of cooling coils. As the tension of the coil spring 54 aids the closing of the valve the member 55 for varying the tension of said coil spring is known as an external superheat adjustment.

The evaporator unit above described is complete in itself, requiring only connection with a liquid refrigerant supply line and with a suction line to complete the refrigerating system. In accordance with the invention the unit is constructed for assembly with other similar units to form an, evaporator of larger size and capacity to suit the requirements of the particular installation. An assembly comprising three units is shown in Figures 5 and 6, the top and bottom flanges E8 of the end members being secured by bolts 58. The several evaporator units are connected in parallel to the suction line 24 and liquid refrigerant supply line 28, which connect with a compressor and condenser to complete the refrigerating equipment. The expansion valve of each unit is responsive to the superheat of the evaporated refrigerant gas which controls the quantity of liquid refrigerant supplied by said valve to the distributor head. The expansion valve and distributor of the evaporator units are disposed so as to locate the distributor head in a horizontal plane whereby the outlet orifices are level and an equal quantity of liquid refrigerant should accordingly be supplied thereto. It is however necessary to maintain the liquid refrigerant evenly distributed over the symmetrically arranged outlet orifices and this function is accomplished by the angular openings provided by the distributor head above the outlet orifices which imparts a whirling motion to the liquid refrig erant flowing therethrough.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. In combination, evaporator structure comprising a plurality of evaporator units connected in parallel to a liquid refrigerant supply line and suction line, each unit including a plurality of evaporator elements, said elements having fins and the end fins of each unit being flanged, means joining the flanged fins of adjacent units, thereby securing the evaporator units to each other, and an expansion valve for each unit for feeding liquid refrigerant to the evaporator elements thereof.

2. In combination, evaporator structure comprising a plurality of evaporator units connected in parallel to a liquid refrigerant supply line and suction line, each unit including a plurality of evaporator elements in parallel relation and joined at one end to a suction header, said evaporator units including flanged end fins, means joining the flanged fins of adjacent units, thereby securing the units to each other, and an expansion valve for each unit for feeding liquid refrigerant to the evaporator elements thereof.

3. In refrigerating apparatus, in combination, evaporator structure including a plurality of elements, a plurality of fins joining said elements together to form a unit, an expansion valve located at one end of said evaporator structure and constructed and arranged to feed liquid refrigerant to said evaporator elements, a suction header joining the other end of said evaporator elements, a suction conduit joining with said suction header and extending along one side of said evaporator structure, the end fins thereof having a recess formed therein for receiving said suction conduit, and a heat interchanger surrounding said suction conduit and extending along that portion thereof located on said side of the evaporator structure.

4. In refrigerating apparatus, in combination, evaporator} structure including a plurality of evaporator elements each comprising a horizontally disposed continuous length of tubing, said elements having fins which join said elements together to form a unit, an expansion valve located at one end of said structure and construoted and arranged to feed liquid refrigerant to said evaporator elements, a vertically disposed header connecting with the other end of said elements, a horizontally disposed suction 1i conduit connecting with said header and extending along one side of said evaporator structure, certain of said fins having a recess therein for receiving said suction conduit, a heat interchanger surrounding said suction conduit and extending along that portion thereof located on said side of the evaporator structure, and a supply line delivering liquid refrigerant to one end of said heat interchanger, the other end thereof connecting with the expansion valve.

5. In refrigerating apparatus, in combination, evaporator structure including a plurality of evaporator elements, said elements having fins which join said elements together to form a unit, an expansion valve for feeding liquid refrigerant to said evaporator elements, a suction header joining the other end of said elements, and a suction conduit connecting with said header and extending along one side of said evaporator structure, certain of said fins having a recess formed therein for receiving said suction conduit.

FRED R. ERBACH. RICHARD H. SWART. 

